Yemen had no shortage of anti-Americanism on Sept. 13 when protesters stormed the U.S. embassy in Sana‘a to express their anger over Innocence of Muslims, an obscure U.S.-made film denigrating the Prophet Muhammad. The day before, the influential leader of Yemen’s Muslim Brotherhood broadcast a sermon praising the violence of protesters in Egypt and Libya for “their denunciation of the film categorically.” Abdul Majid al-Zindani, who was labeled a “specially designated global terrorist” by the U.S. Treasury Department in 2004, exhorted followers to “support your Prophet and declare your wrath, you Muslims, especially you the young men of the Arab revolutions.” Ahmed Dawood, who took part in the riot, told TIME he was recruited by the Zaydi Shi‘ite Houthi movement, which accuses Washington of backing Sana‘a in a six-year shelling campaign of their northern homeland, Sa‘da.

But did Yemeni government soldiers help the rioters enter the embassy in the capital? And if so, were they encouraged by higher-ups with a different agenda?

“They let the protesters in,” Manaa al-Saheer, a witness to the demonstration turned riot at the U.S. embassy in Sana‘a, told TIME, describing how Yemen’s elite Central Security Forces (CSF) who were guarding the compound stood down as the raucous crowd, chanting “Death to America!” and “Victory to Islam!” approached the outer security ring on Thursday.

In the space of a few hours, the throng of mostly young men gutted or set fire to dozens of diplomatic vehicles, scrawled threatening messages across walls, looted property and bludgeoned the bulletproof windows of the embassy’s security building using steel rods and the burnished metal letters of the words American embassy, which they had wrenched from the compound’s sand-colored facade.

After a mob of young men unmoored two towering black wrought-iron gates defending the premises of the embassy itself, others hijacked an armored Chevrolet Suburban, crashing it into the concrete stairway leading to the building’s glass doors, where wide-eyed U.S. troops paced with automatic rifles in hand.

Only once before has any group succeeded in infiltrating the fortress-like U.S. embassy in Sana‘a. The carefully planned attack took place in late 2008, when al-Qaeda militants disguised as policemen besieged the compound with rocket-propelled grenades, automatic rifles and a series of car bombs. Still, they were unable to penetrate the embassy’s inner security ring, which a few hundred mostly young men managed to ransack on Thursday. The embassy’s post-2008 security reinforcements have made it one of the most fortified buildings in the country.

A CSF officer patrolling the embassy a day after the siege told TIME, “We were overwhelmed by the protesters, that’s how they got in.”

That statement puzzled Ibrahim Mothana, a 23-year-old activist who took part in last year’s Yemeni Spring. He recalled CSF units containing thousands of demonstrators on a daily basis simply by firing their guns in the air, the tactic that soldiers ultimately used to disperse protesters on Thursday afternoon after an hour of rioting.

It would be naive to think that Thursday’s infiltration and wholesale destruction of one of the most, if not the most, highly secured buildings in the country was the product of a few hundred angry protesters. A fuller explanation seems to lie in the capital’s tense environment, where rival elites are jockeying for power in an uncertain political landscape.

The peaceful Arab Spring–inspired uprisings of 2011 that unseated 33-year President Ali Abdullah Saleh, a longtime U.S. ally, have entered a state of limbo. With the arrival of interim President Abdel Rabbo Mansour Hadi, the adrenaline-fueled days of revolt in the streets against an iron-fisted authoritarian are fading, and the doldrums of poverty and unpredictability that prevailed in the run-up to the Yemeni Spring appear to have returned.

Hadi is charged with restructuring a deeply corrupt military and unifying Yemen’s factionalized territory ahead of multiparty elections in 2014. Yet while the President has won key battles in his bid to dismantle Saleh’s state-run empire of personal patronage, the changes are coming painfully slowly and their impacts are difficult to gauge. The situation is further exacerbated by the fact that Saleh, having been granted blanket immunity by the international community from any crimes he may have committed during the uprising against him, today leads the country’s ruling party and still wields great influence behind the scenes through his extensive network of family members and allies who owe their top government and military positions to the former President.

In this volatile state of limbo — where President Hadi has made some progress but is nowhere near the light at the end of the tunnel, and where his opponents are starting to fear that the end of their appointments may be nearing — tension abounds.

Hadi’s first two rounds of presidential decrees have succeeded in siphoning Saleh’s military influence but have faced violent consequences. In March, when the President relieved Saleh’s half-brother, Mohammed Saleh al-Ahmar, of his post as commander of the air force, the commander encircled Sana‘a’s international airport with a posse of armed thugs threatening to shoot down planes in protest of his dismissal. Five months later, Hadi targeted the Republican Guard, stripping seven brigades from its commander, Saleh’s eldest son Ahmed, and incorporating three of them into his newly established Presidential Protective Forces. Days later, hundreds of Republican Guards besieged the Defense Ministry in Sana‘a while Hadi was away in Saudi Arabia, triggering a shootout with government forces that killed three.

On the eve of the U.S. embassy attack, the President dismissed stalwart Saleh loyalist Major General Ali al-Anesi from his powerful posts as director of the Presidential Office and chairman of the National Security Bureau, as well as sacked four pro-Saleh governors across the country.

The following morning, CSF forces under the command of Saleh’s nephew Yahya were pictured at a checkpoint outside the embassy signaling the mob of angry protesters to enter the premises. Video footage of the waning moments of the embassy attack showed exhilarated rioters embracing a CSF soldier before sprinting out of the compound.